The present invention relates to an information processor using a disk memory having a disk for use in a portable recording medium capable of reading, writing, erasing, and/or overwriting in a thin rectangular card and a disk memory used therein.
A card which performs read/write of information while rotating a recording medium such as an optical disk and a floppy disk using a tellurium alloy in a flat space is described in JP-A-60-79581.
A magneto-optical disk memory device capable of overwriting by laser power modulation is described in JP-A-62-175948, but a permanent magnet for initializing a magneto-optical disk and a permanent magnet for writing are fixed to an optical disk memory device, and furthermore, an optical head is positioned on an opposite side to the magneto-optical disk. Moreover, in the magneto-optical disk, such a method is adopted that an optical disk medium is fixedly adhered onto a substrate having a thickness of approximately 1.2 mm so as to have light incident from the substrate side as a countermeasure against dust attaching thereto, and the optical disk is contained in a protective case for transportation, thus, requiring a thickness of 6 to 10 mm as the whole optical disk. Because the substrate requires a thickness of 1.2 mm and the permanent magnet for initialization and the permanent magnet for recording are fixed on the opposite side with respect to the optical head and the optical disk in a conventional magneto-optical disk as described above, the thickness of this permanent magnet portion is significant, thus not only making it difficult to miniaturize the optical disk, in particular to form it in a credit card ordered size, but also inhibiting formation of a thin optical disk memory device.
On the other hand, an example in which a disk magneto-optical medium capable of overwriting on a glass substrate having a thickness of 1.2 mm is incorporated in a cartridge, a permanent magnet for application of initializing auxiliary magnetic field is incorporated in the cartridge, and a permanent magnet for recording is installed in a recording device is disclosed in JP-A-64-46247. However, it is difficult to miniaturize and reduce the thickness of an optical disk, in particular to form it in a credit card ordered size when the cartridge is included because a thickness of 1.2 mm is required for the substrate. Further, since the permanent magnet for recording is fixed on the opposite side with respect to the optical head and the optical disk, the thickness of this permanent magnet portion is increased, and thus, there are limitations to making the optical disk memory device thinner. Moreover, there is also such a problem that the laser portion of the optical disk is liable to be damaged because the optical disk is exposed when the window of the cartridge cover is opened.
When a disk capable of reading, writing, erasing, and/or overwriting by a laser power modulation is used as a memory for a lap top computer or other portable information processors, it is desirable to be rectangular in configuration and to be in a card form or a sheet form, in terms of thickness, which is provided with a protective case, for the sake of portability. In a conventional optical disk, however, because the substrate requires a thickness of 1.2 mm as a countermeasure against sticking disk, and particularly in the case of magneto-optical recording, the permanent magnet for initialization and the permanent magnet for recording are fixed on the opposite side of the optical disk with respect to the optical head. Thus, the thickness of this permanent magnet portion is increased, which limits formation of a thin film, and it has been impossible to use such a conventional optical disk in a lap rod computer and a portable optical disk memory device.
As an example for reducing the thickness, a flexible optical disk and a stabilizing plate formed of a translucent material with at least a part thereof being pervious to light are provided as disclosed in JP-A-64-30087. In the case of this optical disk, a disk substrate having the thickness of 1.2 mm as described above is not used. Therefore, the optical disk itself may be formed in a very thin form.
In this case, however, there is no provision in the disk itself at all for removing dust that enters into the case for rotating the optical disk through a hub hole. Thus, such a problem arises that the optical disk is damaged or write/read become impossible with those parts that are covered with dust.
An enclosed type disk has an advantage of not being influenced by foreign dust as compared with a non-enclosed type disk. However, it cannot be avoided that dust generated in a production process will enter into the case, even if the recording medium is totally enclosed. Further, it may happen that dust is generated by friction and the like at a drive portion for rotating the disk. Such dust remains in the case since the space in the case is closed. Thus, it may happen that the dust moves in the case and sticks to a recording area of the disk. As a result, troubles in write/read of information may occur as described above.